add: global registry

go.mod

@@ -3,13 +3,9 @@ module github.com/gogo/protobuf
 go 1.15
 
 require (
-	github.com/golang/protobuf v1.3.5
-	github.com/kisielk/errcheck v1.5.0 // indirect
-	github.com/kisielk/gotool v1.0.0 // indirect
-	golang.org/x/net v0.0.0-20200324143707-d3edc9973b7e // indirect
-	golang.org/x/text v0.3.2 // indirect
+	golang.org/x/net v0.0.0-20201021035429-f5854403a974 // indirect
+	golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 // indirect
 	google.golang.org/genproto v0.0.0-20200324203455-a04cca1dde73 // indirect
 	google.golang.org/grpc v1.28.0
-	golang.org/x/tools v0.0.0-20210106214847-113979e3529a // indirect
+	google.golang.org/protobuf v1.27.1
 )
-

go.sum

@@ -1,45 +1,70 @@
-github.com/kisielk/errcheck v1.1.0 h1:ZqfnKyx9KGpRcW04j5nnPDgRgoXUeLh2YFBeFzphcA0=
-github.com/kisielk/errcheck v1.1.0/go.mod h1:EZBBE59ingxPouuu3KfxchcWSUPOHkagtvWXihfKN4Q=
-github.com/kisielk/errcheck v1.2.0 h1:reN85Pxc5larApoH1keMBiu2GWtPqXQ1nc9gx+jOU+E=
-github.com/kisielk/errcheck v1.2.0/go.mod h1:/BMXB+zMLi60iA8Vv6Ksmxu/1UDYcXs4uQLJ+jE2L00=
-github.com/kisielk/errcheck v1.5.0 h1:e8esj/e4R+SAOwFwN+n3zr0nYeCyeweozKfO23MvHzY=
-github.com/kisielk/errcheck v1.5.0/go.mod h1:pFxgyoBC7bSaBwPgfKdkLd5X25qrDl4LWUI2bnpBCr8=
-github.com/kisielk/gotool v1.0.0 h1:AV2c/EiW3KqPNT9ZKl07ehoAGi4C5/01Cfbblndcapg=
-github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+oQHNcck=
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-github.com/yuin/goldmark v1.2.1/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
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proto/properties.go

@@ -48,6 +48,8 @@ import (
 	"strconv"
 	"strings"
 	"sync"
+
+	"google.golang.org/protobuf/reflect/protoregistry"
 )
 
 const debug bool = false
@@ -597,13 +599,20 @@ func MessageType(name string) reflect.Type {
 
 // A registry of all linked proto files.
 var (
-	protoFiles = make(map[string][]byte) // file name => fileDescriptor
+	protoFiles  = make(map[string][]byte) // file name => fileDescriptor
+	GlobalFiles = newRegistry()
+	globalTypes = new(protoregistry.Types)
 )
 
 // RegisterFile is called from generated code and maps from the
 // full file name of a .proto file to its compressed FileDescriptorProto.
 func RegisterFile(filename string, fileDescriptor []byte) {
 	protoFiles[filename] = fileDescriptor
+
+	err := GlobalFiles.registerRaw(filename, fileDescriptor)
+	if err != nil {
+		panic(fmt.Errorf("proto: unable to register file %s: %w", filename, err))
+	}
 }
 
 // FileDescriptor returns the compressed FileDescriptorProto for a .proto file.

proto/registry.go

@@ -0,0 +1,176 @@
+package proto
+
+import (
+	"bytes"
+	"compress/gzip"
+	"crypto/sha256"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"sync"
+
+	"google.golang.org/protobuf/reflect/protoreflect"
+	"google.golang.org/protobuf/reflect/protoregistry"
+	"google.golang.org/protobuf/runtime/protoimpl"
+)
+
+type hash = [32]byte
+
+func hashDesc(b []byte) hash {
+	return sha256.Sum256(b)
+}
+
+func newRegistry() *registry {
+	return &registry{
+		mu:             new(sync.RWMutex),
+		reg:            new(protoregistry.Files),
+		filepathToHash: map[string]hash{},
+		hashToFilepath: map[hash][]string{},
+		fdByHash:       map[hash]protoreflect.FileDescriptor{},
+	}
+}
+
+type registry struct {
+	mu *sync.RWMutex
+
+	reg *protoregistry.Files
+
+	filepathToHash map[string]hash                      // maps file paths to content hashes
+	hashToFilepath map[hash][]string                    // maps a file descriptor hash to its import paths
+	fdByHash       map[hash]protoreflect.FileDescriptor // maps hash->protoreflect.FileDescriptor
+}
+
+func (r *registry) registerRaw(filepath string, fdZippedBytes []byte) error {
+	fdHash := hashDesc(fdZippedBytes)
+	// check if file is known through its path.
+	knownPath, err := r.knownFilepath(filepath, fdHash)
+	if err != nil {
+		return err
+	}
+	if knownPath {
+		return nil
+	}
+	// this path is unknown, but we might be in the case in which
+	// the same file descriptor bytes are being registered but
+	// with a different path.
+	knownHash := r.knownHash(fdHash)
+	if knownHash {
+		r.registerImportAliasByHash(fdHash, filepath)
+		return nil
+	}
+
+	// if the file is totally unknown then we need to register it
+	zr, err := gzip.NewReader(bytes.NewReader(fdZippedBytes))
+	if err != nil {
+		return fmt.Errorf("bad gzipped file descriptor: %w", err)
+	}
+	fdBytes, err := ioutil.ReadAll(zr)
+	if err != nil {
+		return fmt.Errorf("bad gzipped file descriptor: %w", err)
+	}
+
+	fd := protoimpl.DescBuilder{
+		RawDescriptor: fdBytes,
+		FileRegistry:  r,
+		TypeResolver:  globalTypes,
+	}.Build()
+
+	// save fd info
+	r.saveFileDescriptor(filepath, fdHash, fd.File)
+	return nil
+}
+
+func (r *registry) FindFileByPath(path string) (protoreflect.FileDescriptor, error) {
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+
+	fd, err := r.reg.FindFileByPath(path)
+	if err == nil {
+		return fd, nil
+	}
+	if !errors.Is(err, protoregistry.NotFound) {
+		return nil, err
+	}
+
+	h, exist := r.filepathToHash[path]
+	if !exist {
+		return nil, fmt.Errorf("%w: %s", protoregistry.NotFound, path)
+	}
+
+	return r.fdByHash[h], nil
+}
+
+func (r *registry) FindDescriptorByName(name protoreflect.FullName) (protoreflect.Descriptor, error) {
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+	return r.reg.FindDescriptorByName(name)
+}
+
+func (r *registry) RegisterFile(file protoreflect.FileDescriptor) error {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	err := r.reg.RegisterFile(file)
+	return err
+}
+
+func (r *registry) RegisterImportAlias(original string, alias string) error {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+
+	hash, exists := r.filepathToHash[original]
+	if !exists {
+		return fmt.Errorf("unable to register alias %s for filename %s as it does not exist", alias, original)
+	}
+
+	r.hashToFilepath[hash] = append(r.hashToFilepath[hash], alias)
+	r.filepathToHash[alias] = hash
+
+	return nil
+}
+
+func (r *registry) knownFilepath(filename string, fdHash hash) (bool, error) {
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+	fileHash, known := r.filepathToHash[filename]
+	if known {
+		// if it's known we compare hashes to assert that contents match
+		if fileHash != fdHash {
+			return false, fmt.Errorf("double registration of the same file %s with different content hashes %x <-> %x", filename, fileHash, fdHash)
+		}
+	}
+	// file is unknown
+	return false, nil
+}
+
+func (r *registry) knownHash(fdHash hash) bool {
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+
+	_, known := r.fdByHash[fdHash]
+	return known
+}
+
+func (r *registry) registerImportAliasByHash(fdHash hash, filename string) {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+
+	r.hashToFilepath[fdHash] = append(r.hashToFilepath[fdHash], filename)
+	r.filepathToHash[filename] = fdHash
+
+	_, _ = fmt.Fprintf(os.Stderr, "detected import aliases for files %s", r.hashToFilepath[fdHash])
+}
+
+func (r *registry) saveFileDescriptor(filename string, fdHash hash, fd protoreflect.FileDescriptor) {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+
+	r.fdByHash[fdHash] = fd
+	r.filepathToHash[filename] = fdHash
+	r.hashToFilepath[fdHash] = []string{filename} // this is init always.
+
+	k := make([]string, 0, len(r.filepathToHash))
+	for x := range r.filepathToHash {
+		k = append(k, x)
+	}
+}